This 5-year longitudinal study intends to answer three main questions concerning the menopausal transition: i) can earlier biochemical and clinical markers of the transition be identified that may benefit from early intervention? 2) what are the clinical and biologic features of the menopausal transition and do they differ by ethnic group? 3) what are the relations between these clinical and biological features and hormone profiles of women experiencing the transition to menopause? To address these questions, the UCLA center will enroll a cohort of 500 women, 250 of whom will be Japanese-American and 250 of whom will be Caucasian. At baseline and annually, two types of data will be collected- -collaborative and UCLA-specific. Collaborative data will be collected uniformly at all sites nationwide. This data base will be used to evaluate whether women progress through stages as defined by FSH and cycling status and whether earlier indicators of the menopausal transition can be validated. It will also provide data to evaluate whether there are significant associations between urinary hormone profiles and clinical or biological features of the transition, such as hot flashes. The shared data base will provide a large sample size that will permit stratification by potential effect modifiers, such as sociodemographic characteristics. The UCLA-specific data base is designed to answer relevant questions in the areas of expertise of the UCLA collaborative team. These questions will focus on defining the relation between the menopausal transition and five clinical and biological features: hot flashes, sexuality, mood, health related quality of life, and bone mass. In addition, the UCLA data base will allow comparisons of Japanese women with women from other ethnic groups. UCLA will also conduct two special sub-studies on selected members of our cohort. These will be intensive biological studies of hot flashes and PTH regulation, performed in our Clinical Research Center. UCLA will also conduct validation studies intended to modify of existing instruments and to create new instruments, if necessary, to measure nutritional covariates and biopsychosocial domains in Japanese-American women.